Based on the wetland ecosystem and aiming at the nitrogen cycling process driven by microorganisms, the occurrence characteristics, distribution and nitrogen removal contribution of key links from the level of bacteria were analyzed and summarized, and the cooperative and competitive relationship of each link, the differences of microorganisms at the enzyme level and the characteristics of N2O release were comprehensively analyzed. The comparative analysis shows that nitrogen removal can be achieved in the form of N2 and N2O respectively, and the latter does not meet the requirements of environmental protection. The difference of microorganisms driving the nitrogen cycle in different habitats is due to the difference of enzyme levels of microorganisms. Systematic quantitative evaluation is needed to promote the establishment of regulatory mechanisms for N2O release in wetland ecosystems.